Historically, diagnostic evaluation of a vehicle control system was performed by using designated, generally stand-alone-type testing equipment that was coupled to the specific vehicle's control system. Vehicle control systems have become more computerized with electronic control units being installed in motor vehicles. These control units include one or more micro-controllers which are used to control operation of a variety of vehicular control systems, such as the engine, transmission, brakes or the steering mechanism.
Today in the automotive industry, there are hand-held diagnostic testers or tools used in connection with motor vehicle maintenance and repair. For instance, hand-held diagnostic tools have been used to trouble-shoot faults associated with vehicular control units. Typically such tools have included a micro-processor and an interface circuit to facilitate communication between the vehicle's electronic control unit and the tool's micro-processor. Each diagnostic tool can also included non-volatile internal or external memory, such as a plug-in module, that stores various vehicle component data to provide information to a user. For example, a few of these scan tools can provide a user with schematic wiring diagrams for specific automotive components associated with a given make of vehicle. However, none of the scan tools available to date display the schematic wiring diagram with the wires in color graphics so as to correspond to the actual wire colors between components. Instead, these wiring diagrams are monochrome or grayscale graphics that provide textual indicators, for example, a color code, as to the color of a wire. However, this method of color indicia can be misleading or at least confusing to the automotive technician, because the technician may have to refer to a manual or rely on an assumption to interpret a given color code. Confusion or misinterpretation can lead to misidentification of problem wires and therefore improper diagnosis. This confusion can further lead to delays in repair of the vehicle.
Accordingly, it is desirable to provide a method and apparatus to provide a scan tool capable of displaying wiring diagrams with the wires shown in color graphics corresponding to the colors of the physical wires connecting the automotive components being diagnosed. Such a wiring diagram can provide for quick, easy and accurate identification of wires which in turn can lead to more efficient repair time and a reduction in diagnostic errors.